From the description of patent application WO9839193 a coupler assembly used in the underframe of railway wagons is known. The known solution has two central longitudinal girders positioned on both sides of the wagon's roll axis. The coupler assembly, intended to transfer longitudinal tensile and compressive forces, contains a pulling apparatus located between the rear and front stop in the space between the central girders of the wagon's frame. In such a solution it is also possible to use additional shock absorbing elements, intended to equalise the tractive force and to dampen the braking energy. Due to construction reasons such additional shock absorbing elements may be positioned between the rear stop and the front stop and, in particular: between the front stop and the pulling apparatus, in the pulling apparatus itself or between the rear stop and the pulling apparatus.
From the description of patent EP1431157 an underframe for railway wagons is also known, in which, in order to increase the ability to dampen the energy created by the occurrence of increased compressive forces, an additional shock absorbing head, fixed separately under the central girders of the wagon frame, is used in the coupler assembly.
U.S. Pat. No. 4,345,795 discloses a coupler assembly for coupling railway wagons with a pulling apparatus designated to absorb energy. The coupler assembly comprises a mechanical coupler to be connected to one railway wagon and a coupler support mechanism to be coupled to another wagon. The coupler assembly also includes a cutting ring situated between two tubes movable relative to each other.
US2009/0151595 discloses an energy dissipation device for coupling railway wagons having a damping unit and an increased energy absorption unit used for responding after critical impact force and converting at least a part of impact energy into heat and plastic deformation work.